Doc: Refer to ip-sysctl.txt for strict vs. loose rp_filter mode

The IP_ADVANCED_ROUTER Kconfig describes the rp_filter
proc option.  Recent changes added a loose mode.
Instead of documenting this change too places, refer to
the document describing it:
 Documentation/networking/ip-sysctl.txt

I'm considering moving the rp_filter description away
from the Kconfig file into ip-sysctl.txt.

Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/ipv4/Kconfig b/net/ipv4/Kconfig
index c7a814860ce1..b2cf91e4ccaa 100644
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
@@ -50,6 +50,8 @@ config IP_ADVANCED_ROUTER
           echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter
 
           Note that some distributions enable it in startup scripts.
+          For details about rp_filter strict and loose mode read
+          <file:Documentation/networking/ip-sysctl.txt>.
 
           If unsure, say N here.